Researchers at Bowling Green State University found that the U.S. marriage rate is the lowest it's ever been in over a century at 31.1, which is equivalent to approximately 31 marriages per 1,000 married women. The latest statistics are remarkable compared to statistics in 1920 when the marriage rate was a staggering 92.3.

"Marriage is no longer compulsory," Dr. Susan Brown, co-director of the National Center for Family and Marriage Research, explained in a news release. "It's just one of an array of options. Increasingly, many couples choose to cohabit and still others prefer to remain single."

The study found that the marriage rate has declined by almost 60 percent since 1970 and that the average age at first marriage is the highest it's been in over a century, at nearly 27 years old.

"The age at first marriage for women and men is at a historic highpoint and has been increasing at a steady pace," co-author Dr. Wendy Manning said in a statement.

Researchers found that there has also been a significant increase in the proportion of women who are separated or divorced. Less than 1 percent of women separated or divorced in 1920, compared to 15 percent of women today.

Researcher found that the marriage rate had declined for all racial and ethnic groups, with the greatest decline among African Americans.

The study also found that the education divide in marriage has grown. In the last half-century there have only been modest changes in the percentage of women married among the college educated and the greatest declines among women without a high school diploma.